Process of treating yellowish or off-white materials to obtain a white appearance using umbelliferone or methyl umbelliferone



Patented Mar. 25, 1952 UNITED STATES PATEII'I' OFFICE I 2,590,485 raoccss or? TREATING YELLQWISH R OFF-WHITE MATERIALS T0 WHITE APPEARANCE UMBELLIF" ERONE 0R METHYL UMBELLIFERONE Hans Meyer,,Richmond, England, assignor, by

mesne assignments, to Lever Brothers Company, Cambridge, Mass, a corporation of Maine Section 1, Public Law 690, August 8, 1946 Patent expires J unc 2., 1959 3 Claims. (o1.117--3s.5

This invention relates to a process of treating articles or materials having a yellowish or offwhite appearance or tint so as to obtain a pure white appearance. More particularly, the invention relates to treating these materials with a compound of the coumarin group.

According to the existing practice prior to this invention, when it was desired to obtain as white an appearance as possible on articles, substances or materials, such as textile fabrics, paper and the like, it has been the custom to use ultrairiarine or blue aniline dyes for suppressing or neutralizing undesirable shades. In this way it has not always been possible to obtain consistently the desired results with respect to the white appearance, for the reason that if more than necessary of the above-mentioned ingredients is used, the articles look blue; if less than necessary is used, the articles in some cases take on a greenish appearance, the result of the compensation of the inherent color of the articles with that of the added ultramarine or dyes.

The object of this invention is to produce a still whiter appearance in articles, substances or materials having a yellowish or off-white tint than is possible by previously known procedures. The invention includes the process of accomplishing this result as well as the materials so treated.

The invention is particularly applicable in connection with textile materials, such as yarns, and woven or knitted fabrics, paper and similar pulp products. The composition of the material treatedis not particularly critical and may be of a cellulosic or proteinaceous origin, such as animal or vegetable fibrous materials, synthetic or natural, or modified, regenerated or otherwise treated.

In accordance with the invention, such articles, substances or materials are treated during any stage of their manufacture or subsequently thereto by contacting with, such as by immersion in or otherwise depending upon the character of the material and the time of treatment, a solution of a compound of the coumarin group, preferably umbelliferone and aliphatic or aromatic derivatives thereof, such as methyl umbelliferone or any compound which when dissolved produces a blue fluorescence.

The class of compounds preferred are the hydroxy coumarins, namely compounds of the following general formula:

0:0 (OH). I

where x is a small whole'number of 1 to 4, preferably l, and similar compounds in which one or more of the remaining replaceable hydrogens are replaced by a hydrocarbon radical, for instance aliphatic or aromatic radicals, such as ethyl, methyl: etc. The preferred group of compounds therefore may be said to comprise hydroxy coumarins and their alkyl or aromatic substituted derivatives. Methyl umbelliferone is the preferred species.

In practicing the invention the compound of the coumarin group preferably is dissolved in a solution, such as alcohol or water, preferably the latter because of the simplicity and economic advantage, and the solution contacted with the material to be treated. If the material is a finished textile fabric or yarn, these may be immersed in or drawn through a solution of the compound. Textiles may be treated simultaneously with a washing operation, such as withis not followed by washing or other operations that would remove the compound once it is applied to the material being treated. The amount of the coumarin compound used is not critical except as indicated hereinafter. Preferably enough should be present to secure the desired effect. It is an advantage of the invention that small amounts yield excellent results.

It is alsopreferred in accordance with the invention to include a small amount of a mild alkaline material such as borax, sodium carbonate. alkaline phosphates, soaps, or very small amounts of caustic, for the purpose of rendering the solution slightly alkaline, since this facilitates the solution of the compound and enhances the blue fluorescence which accomplishes the whitening action.

As illustrative of the invention, a textile fabric of yellowish or off-white tint may be treated as follows: the textile fabric is immersed in or 'drawn through a bath containing a strong blue fluorescent solution comprising 10,000 parts by weight of water, about 24 parts of borax and one part of methyl umbelliferone. When the fabrics have been removed from the bath and allowed to 3 dry, they willbe found to have acquired a pure white appearance.

The main advantage of the invention, as compared with existing practice, is that a much purer white is obtained. than has hitherto been possible. A secondary advantage is thatthehigh degree-of whiteness is consistently produced on articles, substances or materials in each category, because any increase beyond a certain minimum of the blue fluorescent compound in the bath does not afiect the degree of whiteness ultimately to be obtained. It is desirable, however, to avoid unneeded excesses of coumarin-type materials because upon oxidation some of these compounds become pink and this might impart an undesired shade to the material treated.

It will be apparent to one skilled in the art, in

view of the disclosure herein that the invention g may be subject to variations and modifications in its mode of operation and practice and I intend all such variations and modifications to be included within the invention as are within the scope of the following claims.

I claim:

1. The process of treating materials having a yellowish ofi-White tint, which comprises contacting the same uniformly with a compound selected from the group consistingof umbellife'rone and methyl umbelliferone which when dissolved produces a blue fluorescence, as the only material to affect the characteristics of the materials being treated, in a solution of a mild alkaline material to facilitate the solubility of the compound and enhance its fluorescence, whereby the yellowish off-white tint is eliminated and a White appearance is obtained.

2. The process of treating materials having a yellowish ofi-white tint, which comprises contacting the same uniformly with umbelliferone which when dissolved produces a blue fluorescence, as the only material to aifect the characteristics of the materials being treated, in a solution of a mild alkaline material to facilitate the solubility of the umbelliferone and enhance its fluorescence, whereby the yellowish cit-white tint is eliminated and a white appearance is obtained.

3. The process of treating materials having a yellowish off-white tint, which comprises contacting the same uniformly with methyl umbelliferone which, when dissolved produces a blue fluorescence, as the only material to affect the characteristics of the materials being treated, in a solution of a mild alkaline material to facilitate the solubility of the methyl umbelliferone and enhance its fluorescence, whereby the yellowish off-white tint is eliminated and a white appearance is obtained.

HANS MEYER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 70,092 Hunter Oct. 22, 1867 564,835 Neumann July 28, 1896 1,488,035 Cruver Mar. 25, 1924 2,089,413 Paine Aug. 10, 1937 2,267,758 Sell Dec. 30, 1941 2,341,009 Axelrad Feb. 8, 1944 FOREIGN PATENTS Number Country Date 89,418 Sweden June 8, 1937 472,473 Great Britain Sept. 17, 1937 522,672 Great Britain June 24, 1940 803,753 France July 20, 1936 874,939 France June 1, 1942 883,435 France Mar. 22, 1943 OTHER REFERENCES Ser. No. 381,856, Wendt, (A. P. 0.), published May 11, 1943.

Melliand Textilberichte, volume 10, (1929) pages 468, 469;. article by P. Krais.

Berichte Deut. Chem. Gesell. (32) 1899, pages 3690 to 3691 (article by Pechmann and Schaal) 

1. THE PROCESS OF TREATING MATERIALS HAVING A YELLOWISH OFF-WHITE TINT, WHICH COMPRIESE CONTACTING THE SAME UNIFORMLY WITH A COMPOUND SELECTED FROM THE GROUP CONSISTING OF UMBELLIFERONE AND METHYL UMBELLIFERONE WHICH WHEN DISSOLVED PRODUCES A BLUE FLUORESCENCE, AS THE ONLY MATERIAL TO AFFECT THE CHARACTERISTICS OF THE MATERIALS BEING TREATED, IN A SOLUTION OF A MILD ALKALINE MATERIAL TO FACILITATE THE SOLUBILITY OF THE COMPOUND AND ENHANCE ITS FLUORESCENCE, WHEREBY THE YELLOWISH OFF-WHITE TINT IS ELIMINATED AND A WHITE APPEARANCE IS OBTAINED. 